Influence of the heat transfer coefficient of cooling devices on the thermal stabilization of railway subgrade foundations

The paper substantiates the use of the heat transfer coefficient of cooling devices as the main criterion for designing thermal stabilization systems for the foundation of the roadbed of transport structures in the cryolithic zone. To assess the influence of the heat transfer coefficient of cooling devices on the thermal stabilization of the roadbed base, numerical modeling was performed for a section of the railway embankment on the Chum-Labytnangi section operated in the Arctic zone. To compile and subsequently verify a numerical model of the railway embankment in operation, the necessary engineering-geological and thermal engineering data were collected and the temperature regime of the “embankment – foundation” system was monitored in an annual cycle. The compiled and verified model was used to study the influence of the heat exchange coefficient of cooling devices on the thermal stabilization of the base of the embankment under consideration. Based on the results of numerical modeling, the dependences of the time of thermal stabilization of the foundation on the heat transfer coefficient during long-term thermal stabilization and for one cold period of the year were determined. Based on the completed research, a design principle for cooling devices for thermal stabilization of the foundations of exploited embankments in the cryolithic zone was formulated. The principle allows one to determine the required heat exchange coefficient, ensuring the design timeframe for thermal stabilization and reducing the amount of frost heaving of transport structures to the maximum permissible values. Based on the results of the conducted research, it was noted that in some cases thermal stabilization solutions may be required that provide a heat transfer coefficient exceeding the capabilities of existing seasonally operating cooling devices. In such cases, research is relevant aimed at developing and effectively implementing solutions based on accelerated or combined thermal stabilization methods, capable of providing higher final values of the heat exchange coefficient between the subgrade and the atmosphere.